* {
  margin: 0;
  padding: 0;
  text-decoration: none;
  list-style: none;
  box-sizing: border-box;
}
body {
  font-family: "montserrat";
}
nav {
  height: 80px;
  width: 100%;
  background-color: #0082e6;
}
label.logo {
  color: white;
  font-size: 35px;
  line-height: 80px;
  padding: 0 100px;
  font-weight: bold;
}
nav ul {
  float: right;
}
nav ul li {
  display: inline-block;
  line-height: 80px;
  margin: 0 5px;
}
nav ul li a  {
  color: white;
  padding: 7px 13px;
  border-radius: 3px;
  font-size: 17px;
  text-transform: uppercase;
}
a.active,a:hover {
  background-color: #1b9bff;
  transition: .5s;
}
.checkbtn {
  font-size: 30px;
  color: white;
  float: right;
  line-height: 80px;
  margin-right: 40px;
  cursor: pointer;
  display: none;

}
#check {
  display: none;
}
/* 当前屏幕最大只有925时才生效的样式 */
@media(max-width:925px) {
  label.logo {
    font-size: 30px;
    padding-left: 50px;
  }
  nav ul li a {
    font-size: 16px;
  }
}
/* 当前屏幕最大只有858时才生效的样式 */
@media(max-width:858px) {
  .checkbtn {
    display: block;
  }
  nav ul {
    position: fixed;
    width: 100%;
    height: 100vh;
    top: 80px;
    right: -100%;
    background-color: #2c3e50;
    text-align: center;
    transition: all .5s;
  }
  nav ul li {
    display: block;
    margin: 50px 0;
    line-height: 30px;
  }
  nav ul li a {
    font-size: 20px;
  }
  a.active,a:hover {
    background: none;
    color: #0082e6;
  }
  #check:checked ~ ul {
    right: 0;
  }
}
section {
  background: url(../resource/centuryClock.JPG) no-repeat;
  background-size: cover;
  height: calc(100vh - 80px);
  width: 100%;
}